BEIJING  A sewage leak from a chemical plant has spilled the cancer-causing chemical arsenide into a river in central China's Hunan province, poisoning drinking water for nearly 100,000 locals, Chinese media said.

Residents in Yueyang county were asked to stop drinking tap water and 18 fire engines distributed fresh water, the official Xinhua news agency reported on Saturday.

Fresh water from a nearby reservoir was being discharged into the river in an attempt to dilute the polluted water.

Xinhua said Hunan environmental authorities had detected arsenide levels in the Xinqiang river at 10 times the normal standard, after the case was first reported on Friday.

It said arsenide can damage the liver, kidney and cause lung or skin cancer, as well as cause convulsions which may lead to coma or even death.

A chemical plant in Linxiang city, 50 km (30 miles) upriver, was has been ordered closed after it was found leaking the toxin from its waste water pond.

Rapid expansion in such safety-hazardous industries like chemical and smeltering has led to an increasing number of pollution cases in China.

Last week a lead smelter in northwest Gansu province poisoned 2,000 people.